• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.195-204
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• 2010

Several quality parameters affecting Alaska pollack, Theragra chalcogramma, were measured and modeled kinetically under storage at different temperatures: the K-value, trimethylamine (TMA), volatile basic nitrogen (VBN), Torry meter, pH, acid value (AV), total viable cell count (TVC), and colony forming units (CFU) of Pseudomonas spp. The off-flavor development time (ODT) was also measured using the R-index sensory test and modeled kinetically. Among the quality parameters, the CFU of Pseudomonas spp. was an indicator of the ODT according to a similarity in the Arrhenius temperature dependence, which was derived as a criterion mathematically. The temperature dependence was represented by the Arrhenius's activation energy ($E_a$). On comparing the $E_a$ of the quality factors and the ODT, the similarity in the temperature dependence was found to be high in the order Pseudomonas spp., pH, VBN, TVC, K-value, TMA, AV, and Torry meter. Therefore, Pseudomonas spp. was identified as the primary indicator of ODT.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.91-94
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• 2018

We develop a time-temperature indicator (TTI) that can determine whether thawing of fish and other fishery products has occurred during frozen storage. A polypropylene tube with an internal diameter of 3 mm was prepared and cut to a length of 14 to 20 mm. One end of the tube was thermally sealed and 0.1% acetic acid was injected into the other end; the tube was then frozen at $20^{\circ}C$. Then the open side of the frozen tube was blocked by sinking the tube into a 10% gelatin solution. The tube was attached to a polyvinyl packaging bag along blue litmus paper and the bag was put into a freezer at $-20^{\circ}C$. After freezing, the bag was removed to an ambient temperature of $20^{\circ}C$, and the time dependence of the color change of the litmus paper was observed. The color changed from blue to red, with the length of the red region increasing with time. Our TTI can be used as a part of a visible detection system and the detection program can conduct the elapsed time analysis on the length of the red region of the litmus paper indicating the degree of thawing. Thus, the TTI is a useful tool in the temperature management of frozen fish and fishery products.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.448-457
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• 2012

The predictive ability for off-flavor development and quality change of ground beef was evaluated using a microbial time temperature indicator (TTI). Quality indices such as off-flavor detection (OFD) time, color, pH, volatile basic nitrogen (VBN), aerobic mesophilic bacteria (AMB) counts, and lactic acid bacteria (LAB) counts were measured during storage at 5, 10, 15, and $25^{\circ}C$, respectively. Arrhenius activation energies (Ea) were estimated for temperature dependence. The Ea values for TTI response (changes in titratable acidity (TA)), VBN, AMB counts, LAB counts, and freshness, which is defined based on OFD time for quality indices of ground beef, were 106.22 kJ/mol, 58.98 kJ/mol, 110.35 kJ/mol, 116.65 kJ/mol, and 92.73 kJ/mol, respectively. The Ea of microbial TTI was found to be closer to those of the AMB counts, LAB counts, and freshness. Therefore, AMB counts, LAB counts, and freshness could be predicted accurately by the microbial TTI response due to their Ea similarity. The microbial TTI exhibited consistent relationships between its TA change and corresponding quality indices, such as AMB counts, LAB counts, and freshness, regardless of storage temperature. Conclusively, the results established that the developed microbial TTI can be used in intelligent packaging technology for representing some selected quality indices of ground beef.

• Food Science and Preservation
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• v.15 no.4
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• pp.491-496
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• 2008

To develop a freshness indicator of Chonggak-kimchi for marketing purposes, Chonggak-kimchi was prepared and pH, total acidity, total aerobic bacterial load, lactic acid bacterial levels, and reducing sugar content were measured. Sensory evaluation tests on product stored at $4^{\circ}C,\;10^{\circ}C,\;and\;20^{\circ}C$, were performed. The pH increased slightly early in storage, and then decreased to pH 4.2-4.3 for all samples. The rate of decrease of pH rose with increasing storage temperature. Total acidity values rapidly increased after 1, 5, and 7 days of storage at $20^{\circ}C,\;10^{\circ}C,\;and\;4^{\circ}C$, respectively. Populations of total aerobic bacteria and lactic acid bacteria increased slightly until 4 days, 10 days, and 30 days of storage at $20^{\circ}C,\;10^{\circ}C,\;and\;4^{\circ}C$, respectively, and then decreased drastically. Sensory evaluation data showed that Chonggak-kimchi was edible until 4 days(pH 4.5), 10 days(pH 4.4), and 30 days(pH 4.3) of storage at $20^{\circ}C,\;10^{\circ}C,\;and\;4^{\circ}C$, respectively. These results clearly suggest that the shelf-life of Chonggak-kimchi depends on storage temperature, and the pH limit for marketing is 4.3; this is a freshness indicator for Chonggak-kimchi.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1168-1174
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• 2017

Objective: The aim of the study was to evaluate the effects of different nitrate levels (150, 300, 450, and 600 ppm $KNO_3$) on the volatile compounds and some other properties of pastırma. Methods: Pastırma samples were produced under the controlled condition and analyses of volatile compounds, and thiobarbituric acid reactive substances (TBARS) as an indicator of lipid oxidation, non-protein nitrogenous matter content as an indicator of proteolysis, color and residual nitrite were carried out on the final product. The profile of volatile compounds of pastırma samples was analyzed by gas chromatography/mass spectrometry using a solid phase microextraction. Results: Nitrate level had a significant effect on pH value (p<0.05) and a very significant effect on TBARS value (p<0.01). No significant differences were determined in terms of $a_w$ value, non-protein nitrogenous substance content, color and residual nitrite between pastırma groups produced by using different nitrate levels. Nitrate level had a significant (p<0.05) or a very significant (p<0.01) effect on some volatile compounds. It was determined that the amounts and counts of volatile compounds were lower in the 450 and especially 600 ppm nitrate levels than 150 and 300 ppm nitrate levels (p<0.05). While the use of 600 ppm nitrate did not cause an increase in residual nitrite levels, the use of 150 ppm nitrate did not negatively affect the color of pastırma. However, the levels of volatile compounds decreased with an increasing level of nitrate. Conclusion: The use of 600 ppm nitrate is not a risk in terms of residual nitrite in pastırma produced under controlled condition, however, this level is not suitable due to decrease in the amount of volatile compounds.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.325-330
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• 2006

To determine freshness and detect changes in quality of beef and pork during storage, we manufactured a freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, electronic nose analysis, and sensory evaluation. Both beef loin and pork belly had a change in the color of the freshness indicator after storage of 6 days at $2^{\circ}C$. VBN and TBARS levels and total bacterial counts reached the decay point at the time of the color change of the freshness indicator attached to the surface of the beef and pork samples. Sensory evaluation also indicated that the samples were unacceptable by an 'off' odor on day 6 of storage. There were significant differences in electronic nose analysis for samples from day 0, day 6, and day 10 of storage. These results suggest that this freshness indicator should be useful in determining the expiration date of beef and pork products during marketing by indicating the microbial safety as well as the physicochemical and sensory changes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.761-767
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• 2006

To determine freshness and quality change of chicken products during storage, we manufactured freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, electronic nose analysis, and sensory evaluation. All chicken products (drum, wing, thigh) had a change in color of freshness indicator after storage of 3 days at $4^{\circ}C$, indicating poor quality at the time. VBN, TBARS values, and total bacterial counts reached the decay point at the time of color change of freshness indicator attached to the surface of chicken samples. The sensory evaluation also indicated sample was not acceptable by off-odor at day 4 of storage. According to electronic nose analysis to examine off-odor, there were significant differences in terms of principal component analysis values among chicken samples of day 0, day 3, and day 5 of storage. These results suggest that freshness indicator should be useful in determining expiration date of chicken products during marketing by indicating the microbial safety as well as physicochemical and sensory change.

• The Korean Journal of Food And Nutrition
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• v.34 no.5
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• pp.477-486
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• 2021

To utilize Malus pruniforia Borkh. as a functional material, cold-water (CW), hot-water (HW), and 70% ethanol (EtOH) extracts were prepared, and their antioxidant and anti-inflammatory activities were compared. The antioxidant activity of the HW extract evaluated by ABTS and DPPH radical scavenging and FRAP activity was significantly effective. The total polyphenol content of the HW extract was also higher by 15.5±0.7 mg GAE/g extract compared to other extracts. The EtOH extract showed significantly decreased TNF-α (39.8%), IL-6 (65.5%), and NO (34.9%) levels in RAW 264.7 cells compared to the LPS-induced control group. The levels of IL-6 (21.1%) and IL-8 (19.3%) were significantly decreased by treatment of EtOH extract in HaCaT keratinocytes induced with TNF-α and IFN-γ. The UHPLC-MS results indicated that the EtOH extract might have chlorogenic acid and phlorizin as the major compounds. This was validated using HPLC-DAD, which showed that the EtOH extract had higher levels of chlorogenic acid and phlorizin (1,185±58 and 470±10 ㎍/g extract, respectively). In conclusion, the present study suggested that the anti-inflammatory activity of the EtOH extract was more effective than the CW and HW extracts, and chlorogenic acid and phlorizin could be used as indicator compounds and functional substances.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.4
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• pp.470-476
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• 2013

The property of deep frying oil is one of the important factors in fried food quality. The purpose of this study is to identify the quality of deep frying oil in continuous usages for 4 days by two types of fryers: traditional deep-fat fryer and modified oil-water fryer. After frying pork cutlets, the frying oil was kept not only for several physical analyses such as color, viscosity, and water content but also for the quality analyses of frying oil, such as free fatty acid, double bond changes and oxidative rancidity formation. The oil fried in a traditional deep-fat fryer was significantly increased in terms of physical values including moisture content, viscosity, and color, compared to those of the modified fryer, continuously for 4 days. The oil fried by a traditional deep-fat fryer exhibited a significant increase in its free fatty acid content compared to that fried by a modified oil-water fryer, while the iodine value was significantly decreased in the oil fried by a traditional deep-fat fryer when compared to control oil and oil fried by the modified oil-water fryer. In the peroxide value as an indicator of primary oxidation products, the oil fried by both fryers was significantly increased till the second day but decreased in value after the third day because of unstable hydroperoxide decomposition. The p-anicidine value is used as an indicator of secondary oxidation products, the oil fried in a traditional deep-fat fryer was significantly increased in value compared to that of a modified oil-water fryer.

• Analytical Science and Technology
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• v.16 no.2
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• pp.166-173
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• 2003

To determine levels of PCBs in food, beef, pork, chicken, egg, mackerel, yellow croaker, anchovy, common squid and little neck clam were chosen and collected at markets in Seoul, Busan and Kwangju. Among 209 PCB congeners, 7 congeners (#28, #52, #101, #118, #138, #153 and #180) were selected as target compounds that were known as indicator congeners. Samples were homogenized, treated in alkali solution for 1 hour, and extracted with organic solvents. After extraction, extracts were cleaned up by sulfuric acid, purified on silica gel column chromatography, analyzed by dual column-HRGC/ECD and then confirmed by HRGC/MSD. As results, PCBs were detected in fish samples ranged from 0.0002 to 0.001 mg/kg. Both PCB #101 and PCB #118 were the major contributors among 7 congeners.